How do you determine the number of atoms in 28.7 grams of gold (Au)
1 mole of Au = 196.96g = 6.022 x 10^23 atoms
28.7g * 6.022 x 10^23atoms/196.96g =
To determine the number of atoms in a given amount of a substance, you can use the concept of molar mass and Avogadro's number.
Step 1: Find the molar mass of gold (Au).
The molar mass of gold is calculated by adding the atomic masses of its constituent atoms. The atomic mass of gold can be found on the periodic table. The atomic mass of gold (Au) is approximately 197.0 grams per mole (g/mol).
Step 2: Convert grams to moles.
To convert the given mass of gold (28.7 grams) to moles, you need to divide it by the molar mass of gold:
28.7 g ÷ 197.0 g/mol = 0.1459 mol.
Step 3: Use Avogadro's number to convert moles to atoms.
Avogadro's number is approximately 6.022 x 10^23 atoms per mole. To find the number of atoms, multiply the number of moles (0.1459 mol) by Avogadro's number:
0.1459 mol x 6.022 x 10^23 atoms/mol = 8.788 x 10^22 atoms.
Therefore, there are approximately 8.788 x 10^22 atoms in 28.7 grams of gold (Au).